Method of fitting of resilient elements for the dynamic allospondyledesis purposes, and the relevant device to enable application of the method

ABSTRACT

Method of fitting the resilient elements used for the dynamic allospondyledesis purposes, aimed at correction and stabilizing the injured vertebral column with a simultaneous measuring of applied forces, consists in making a preliminary measurement of the length of springs and catches forming the resilient system to be fitted on the injured vertebral column or backbone, and in subsequent determining the value of pressure exercised by the catches against the backbone vertebrae. The resilient system will be put into the stretcher yokes, matched or adjusted to the backbone preselected vertebrae spacing, then fitted to the backbone indicated section and the stretcher released to determine the spring elements characteristic. According to this invention, the device to enable fitting the resilient system, consists of arms 1 with yoke type end links 2 being rigidly coupled with the thrusting control levers 3, and the basic resilient system being attached thereto.

Weiss et al.

[ Nov. 4, 1975 METHOD OF FITTING OF RESHJIENT ELEMENTS FOR THE DYNAMIC ALLOSPONDYLEDESIS PURPOSES, AND THE RELEVANT DEVICE TO ENABLE APPLICATION OF THE METHOD [75] Inventors: Marian Weiss, Konstancin; Zdzisiaw Bentkowski, Warsaw; Sylwester Sokulski, Jeziorna, all of Poland [73] Assignee: Akademia Medyczna, Warsaw,

Poland [22] Filed: July 18, 1974 [21] Appl. No.: 489,780

52 us. Cl. 128/69 51 Int. cl. A61F 5/00 58 Field of Search 128/69, 92, s3

[56] References Cited UNITED STATES PATENTS 1,424,884 8/1922 Deane 128/69 2,180,775 11/1939 Stevens..... 128/69 2,593,624 4/1952 Stevens 128/69 Primary Examiner-Richard A. Gaudet Assistant Examiner-J. Yasko Attorney, Agent, or Firm-Waters, Schwartz & Nissen [57] ABSTRACT Method of fitting the resilient elements used for the dynamic allospondyledesis purposes, aimed at correction and stabilizing the injured vertebral column with a simultaneous measuring of applied forces, consists in making a preliminary measurement of the length of springs and catches forming the resilient system to be fitted on the injured vertebral column or backbone, and in subsequent determining the value of pressure exercised by the catches against the backbone vertebrae. The resilient system will be put into the stretcher yokes, matched or adjusted to the backbone preselected vertebrae spacing, then fitted to the backbone indicated section and the stretcher released to determine the spring elements characteristic.

According to this invention; the device to enable fitting the resilient system, consists of arms 1 with yoke type end links 2 being rigidly coupled with the thrusting control levers 3, and the basic resilient system being attached thereto.

2 Claims, 2 Drawing Figures US. Patent Nov. 4, 1975 METHOD OF FITTING OF RESILIE'NTELEMENTS FOR THE DYANMIC ALLOSPONDYLEDESIS PURPOSES, AND THE RELEVANT DEVICE TO ENABLE APPLICATION OF THE METHOD This invention covers a method of fitting of resilient systems used for .thedynamic allospondyledesis purposes, and the relevant device or appliance to enable application of the method concerned. The method according to the inventiionis aimed at the vertebralcolumn or backbone correction and stabilization, with a simultaneous measuring of forces being applied to se cure the said object. The device enabling practical application of the method according to this invention, consists of a lever type stretcher coupled with the resilient system. The invention is particularly applicable for surgery of fractured vertebral'column with injured s'pi nal cord, or in case of fractured spinal cord itself.

A method has been known, which consists in fitting a double toothed bar to the backbone. Such a bar embraces the processes on about five vertebrae and locks causing a thorough stiffening of the backbone selected section.

A device has been known, which enables practical application of the said method and consists of an H- shape with sharp incisions on internal faces thereof.

Method and device have been known as published in papers of the surgery symposium held in the town of Otwock, Poland, in May, 1972.

The hitherto known methods suffer from many drawbacks consisting in a lack of forces to compress the injured backbone vertebrae, and thus to counteract their deformation and harmful displacement thereof. The hitherto method does not enable an autocorrection of the vertebrae mutual position, nor a reversible return of the movable system comprising the mechanical parts and the backbone to the initial posture, and thus the said system can not recover-its state of equilibrium i.e. the dynamic stability.

Using of the hitherto known device calls for excising one vertebra process. The known device produces but a very small intercompression of the vertebral column, on the other hand causing a local crush to the bone tissue.

The purpose of this invention is to eliminate the said drawbacks and inconveniences, primarly the insufficient pressure, and the lack of correction and stability.

To secure this object, a method had to be elaborated, which enables stabilizing of the injured backbone vertebrae by means of mechanical resilient elements, and

a relevant device developed offering a precise prepara-.

tion of the corrective resilient system, fitting the latter to the injured backbone and determining the device characteristic as regards springing forces and pressureexercised upon the vertebra bones, even before the operation is finished and without a necessity for causing any loss to the backbone vertebrae.

THE INVENTION ESSENCE The technical solution according to this invention is characterized by having a stretcher consisting of yoke .iended arms with rigidly linked control levers and the ?attached resilient system.

According to this invention, the resilient unit will be placed in the stretcher yokes, and the disposition of elements will be matched to the space between each of 40 selected vertebrae. On the backbone selected section the stretcher will be fitted and "then released; thereafter, the resilient system characteristic will be recognized by determining the resultant force of springs and pressure'exercised by catches upon the vertebral bones in order to establish the degree of hazard produced to them.

" In the drawings:

FIG. Us a perspective view of the invention;

FIG. 2 is an enlarged view of one of the catches of the invention.

The invention method consists in locating the catches 6 and measuring the distance between the catch points. With reference to the characteristic .curve of the springs used, the reduced length of the springs 4 and their pressure value will be determined. The resilient system will be fitted in the lever type stretcher yokes. In result of turning the knobs 9, the screw 8 via the thrusting levers 7 causes departure of the springs 4 stretcher arms 1 to cover the distance between the am catch points. With the resilient system prepared as above, measurements of tension and elongation will be taken, properties and actual load of springs will be checked and compared with the spring characteristic. Should the admissible limits be exceeded, another set of springs will be used. By means of the lever 3 and the yoke 2, the prepared resilient system will be fitted to the backbone predetermined section. By reversing the knob 9, the conical plates or blocks 5 become moved spring connected with conical plates having appropriate profiled catches, which enable associating this system with the stretcher before the whole is fitted on the injured vertebral column. This invention inherent method results in quite unique effects viz. it does enable application of required forces to the injured section, in the desired direction and the force application backbone, an automatic decrease of spring pressure will take place the lower are the counteracting forces developed by the vertebral column bones. The resilient system according to this invention offers the backbone dynamic correction with time, and a simultaneous stabilization thereof. Verified and registered scope and direction of forces developed by the resilient system, ensuring the backbone vertebrae stabilization, can remain within the human body for at least 1 year. This invention executive example is shown in the attached drawing, which represents the lever type stretcher coupled with the resilient system in side view.

As may be seen from the drawing, the stretching arms I of the springs 4 being applied to the backbone selected section, are terminated with yoke elements 2 and linked with the thrusting levers 3. The springs 4 are ended with conical plates 5 and profiled catches 6. Both arms 1 of the stretcher are connected through the yokes 7 with the stretcher screw 8 equipped with the knob 9.

This invention inherent method consists in locating the catches 6 and subsequent measuring the distance between the catch points. With reference to the characteristic curve of the springs used, the reduced length of the springs 4 and their pressure value will be determined. The resilient system will be fitted in the lever type stretcher yokes. ln result of turning the knobs, 9, the screw 8 via the thrusting levers 7 causes departure of the springs 4 stretching arms 1 to cover the distance between the a m catch points.

With the resilient system prepared as above, measurements of tension and elongation will be taken, properties and actual load of springs will be checked and compared with the spring characteristic, Should the admissible limits be exceeded, another set of springs will be used. By means of the lever 3 and the yoke link 2, the prepared resilient system will be fitted to the backbone predetermined section. By reverse turning the knob 9, the conical plates or blocks become advanced from the yokes 2. Then, the springs actual tension change will be determined and another set of springs should be used if the required tension is found lost as indicated by the spring turn-to-turn pitch measurement.

- We claim:

1. Device to enable fitting resilient spring elements used for the dynamic allospondyledesis purposes, comprising. in combination structure means with stretcher arms, yoke links catches at the said stretcher arms connected by a pair of thrusting levers and a screw member disposed between said levers which when rotated causes displacement of the spring means between the Catch links.

2. A method of fitting resilient spring elements used for the dynamic allospondyledesis purposes, comprising the steps of measuring the length of backbone section to be within the reach of catches and springs, determining the required pressure force, selecting the spring so that the measured length has half of the re- "quired pressure force, said pressure force being a predetermined force, locating catches on the springs ends and fitting the unstretched set in stretcher yokes, stretching the spring to a predetermined length, locating the catches said catches being connected by the spring on the backbone section, removing the catches and loosening the tension measuring the length of the spring located on the backbone, and comparing the actual state of the tension force of the spring to predeterinined characteristics of the spring. 

1. Device to enable fitting resilient spring elements used for the dynamic allospondyledesis purposes, comprising in combination structure means with stretcher arms, yoke links catches at the said stretcher arms connected by a pair of thrusting levers and a screw member disposed between said levers which when rotated causes displacement of the spring means between the catch links.
 2. A method of fitting resilient spring elements used for the dynamic allospondyledesis purposes, comprising the steps of measuring the length of backbone section to be within the reach of catches and springs, determining the required pressure force, selecting the spring so that the measured length has half of the required pressure force, said pressure force being a predetermined force, locating catches on the springs ends and fitting the unstretched set in stretcher yokes, stretching the spring to a predetermined length, locating the catches said catches being connected by the spring on the backbone section, removing the catches and loosening the tension measuring the length of the spring located on the backbone, and comparing the actual state of the tension force of the spring to predetermined characteristics of the spring. 